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Resource leveling: A practical approach

9 replies [Last post]
Carlos Arana
User offline. Last seen 3 years 12 weeks ago. Offline
Joined: 6 Jun 2009
Posts: 178
Watch the next video



Lets create a scenario:
They must throw 30 cubic meters of sand from street level to roof level.
They start working in the morning at 8:00, then work 4 hours and then go to eat, they come an hour later and then they keep working from 13:00 to 17:00

Questions:
When are workers at street level free to work in another crew?
What is the shortest time when the work will be done?

I don’t have the answers, we must figure them out.

Best Regards,
Carlos.

Replies

Rafael Davila
User offline. Last seen 4 hours 34 min ago. Offline
Joined: 1 Mar 2004
Posts: 5073
Rashid,

The Troublesome Toilet Seat: Up or down, can be viewed as a Queuing Simulation Problem.

http://www.speech.sri.com/people/anand/toiletseat/index.html

Best Regards,
Rafael
Rashid Iqbal
User offline. Last seen 1 year 37 weeks ago. Offline
Joined: 7 Apr 2010
Posts: 67
Carlos,

Rafael got it right....and you know it has benfits but construction is not that complex as this simulation is.

It can be used to for disruption claims. Thanks.

r
Rafael Davila
User offline. Last seen 4 hours 34 min ago. Offline
Joined: 1 Mar 2004
Posts: 5073
Carlos,

From Wikipedia:

In mathematics, a deterministic system is a system in which no randomness is involved in the development of future states of the system.

You never know when and which one on top of the tower is going to piss and to whom. It is not really a steady flow process, is going to happen at random. Queuing models can work here but in 30 years never had the need to use such esoteric tools, more for the academics in need to Publish or Perish.

Better assume it is steady on average and model volume lag, keep it simple and make sure you are wearing a raincoat.

Best Regards,
Rafael
Carlos Arana
User offline. Last seen 3 years 12 weeks ago. Offline
Joined: 6 Jun 2009
Posts: 178
Yes you are right, this is a process. Congratulations for your great teachers, now please if you may illuminate me a little further, what should I understand for "Deterministic" ??

Best Regards,
Carlos.
Rashid Iqbal
User offline. Last seen 1 year 37 weeks ago. Offline
Joined: 7 Apr 2010
Posts: 67
Here I want to add...

It is a process or an operation ...lets not consider it as porject. in Project planning, project is broken down to activties whereas for optimizing an operation simulation techniques are used. In short...process is divided to cycles, determinstic durations are not used in simualtion.

Simman AbouRizk, Dany Hajjar have done a lot of work in this field. I had the privilage to be a student of AbouRizk and he was my supervisors for my masters final report.

See the article below, this will give you are rough idea as what simulation is all about.

Simphony: an integrated environment for construction simulation
by: Simaan AbouRizk and Yasser Mohamed
Carlos Arana
User offline. Last seen 3 years 12 weeks ago. Offline
Joined: 6 Jun 2009
Posts: 178
They’re real resources on levels. Yes it was fun to watch at first but I think It has some important lessons to teach if you try to schedule what is happening in the video, each level has limited space and you have limited resources, but in the end it is true what Vladimir says: the crew with the minimal productivity will define the overall duration, it may not be as complicated as I initially thought.

I have other fun construction videos, I’ll post them this weekend when I have open YouTube.

Best Regards,
Carlos.
Rashid Iqbal
User offline. Last seen 1 year 37 weeks ago. Offline
Joined: 7 Apr 2010
Posts: 67
Carlos,


It is very interesting....

In some places of the world manpower is the most expensive item in a project and in some places it is the other way around.

Regards
R
Carlos,
the crews on each level have similar productivities, and if the productivity of one crew is larger then the resources in other crew will have some spare time and have not 100% workload but 85% or something like that. The crew with minimal productivity will define the overall duration.
This is resource planning - the calculations shall be done before resource assignments. You shall define what crews to assign considering the restrictions (space) and resource productivities. You will know the workloads of each crew.
This is how I understand ladder relationships with volume SS and FF lags.
Best Regards,
Vladimir
Rafael Davila
User offline. Last seen 4 hours 34 min ago. Offline
Joined: 1 Mar 2004
Posts: 5073
Carlos,

You have 4 men at ground level while 2 at top of the tower, this is an issue of volume lag. What if one on top of the tower got to go for a piss, is he /she going to do it there? Well you got to give some incentive to work on top of the tower. If working at street level I would wear a raincoat.

I did a job on a tower, a little bit higher and one day I was asked to go to the top, I replied I must go to the porto-let every ½ hour. The Owner’s PM thought I was to use the ladder. I did go to the top of the 400ft concrete tower once the personnel hoist was installed.

Is easier if you use the appropriate equipment, anyway the video is funny.

Best regards,
Rafael